Dynamic information storage or retrieval – Information location or remote operator actuated control – Selective addressing of storage medium
Reexamination Certificate
1998-08-04
2001-04-24
Neyzari, Ali (Department: 2651)
Dynamic information storage or retrieval
Information location or remote operator actuated control
Selective addressing of storage medium
C369S044280, C235S454000
Reexamination Certificate
active
06222798
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an optical information recording and reproducing method and device, and more particularly, to an optical information recording and reproducing method and device, whereby improvement can be made in the performance of track jump operations of a light beam spot to a desired information track on a card-shaped optical recording medium, whereon a plurality of information tracks are formed mutually in parallel.
2. Description of the Related Art
In many optical information recording and reproduction devices, whereby information is recorded onto and reproduced from an optical information recording medium whilst causing the recording medium to move at high speed relative to an optical head emitting a light beam spot, a card-shaped recording medium, in other words, a recording medium called an optical card, is used.
Here,
FIG. 6
shows the composition of a general optical card.
As
FIG. 6
shows, the optical card
500
comprises several thousand or several ten thousand information tracks
504
formed mutually in parallel in an information recording region
501
thereof, and information is recorded by shining a light beam spot onto the central region
502
(region represented by p×q surface area) of these information tracks
504
to form pits, and information is reproduced by detecting the presence or absence of pits from the reflected light of the light beam spot.
In addition to forming pits when recording information on the central region
502
, pre-formatted information, such as address information for specifying data groups or information tracks
504
required for acquiring bit synchronization, is recorded previously by creating pits.
On the other hand, the end regions
503
(regions represented by r×q surface area) of the information tracks
504
are regions for accelerating and decelerating in order that the optical card is moved at a constant speed relative to the optical head, so no pits are formed in these regions.
FIG. 7
is a diagram giving a partial enlarged illustration of the information recording region
501
of the optical card
500
.
Information tracks
504
(
504
-
1
,
504
-
2
,
504
-
3
) and guide tracks
505
(
505
-
1
-
505
-
4
) are formed on the information recording region
501
, and pre-formatted data pits
506
constituting pre-formatted data, such as address information, and the like, and recording pits
507
constituting data recorded by the user are formed on the information tracks
504
, the absence or presence or these pre-formatted data pits
506
or recording pits
507
representing the respective data types.
The guide tracks
505
are regions of different reflectivity to the information tracks
504
, and they are used for autotracking (hereinafter, abbreviated as AT) control in order that the optical information recording and reproduction device does not deviate from the information track
504
when scanning a desired information track
504
.
FIG. 8
is a block diagram showing the composition of an optical information recording and reproduction device, and
FIG. 9
is an approximate diagram showing the composition of an optical head.
In
FIG. 8
, the optical information recording and reproduction device
510
comprises: a CPU (Central Processing Unit)
511
for overall control of the device; an MPU (Microprocessor Unit)
512
for controlling the section relating to the recording and reproduction operations of the device, on the basis of the control implemented by the CPU
511
; a modulating and demodulating circuit
513
for modulating data being recorded and demodulating data being reproduced; an optical head
514
for creating and detecting recording pits
507
, and the like; a y-direction drive motor
515
which drives the optical head
514
reciprocally in the y direction; an x-direction drive motor
516
which drives the optical card
500
reciprocally in the x direction; a track jump circuit
517
for controlling track jumping; an AF/AT control circuit
518
for performing autofocussing (hereinafter, abbreviated as AF) control and AT control such that a focused light beam spot is shined onto the surface of the light card
500
at all times, even if there are fluctuation in this surface; and a movement speed detecting circuit
519
for detecting the speed of movement of the optical card
500
.
Furthermore, as shown in
FIG. 9
, the optical head
514
comprises: a semiconductor laser
541
, collimator lens
542
, diffraction grating
543
, beam splitter
544
, object lens
545
, light receiving lens
546
, photoreceptor
547
, and actuator
548
. Laser light output from the semiconductor laser
541
is formed into parallel light by the collimator lens
542
and split by the diffraction grating
543
into three beams, which are shined via the beam splitter
544
and object lens
545
onto the optical card
500
as beam spots
550
. The reflected light from the beam spots
550
shined onto the optical card
500
passes through the object lens
545
, beam splitter
544
and light receiving lens
546
and is converted to an electrical signal by the photoreceptor
547
. Since one of the three beam spots shined onto the optical card
500
is shined onto an information track
504
, and the other two beam spots are shined onto the guide tracks
505
on either side of this information track
504
, the reflected light, in other words, the signal converted to an electrical signal by the photoreceptor
547
, contains a focussing control signal and tracking control signal in addition to a data signal. In order for the optical recording and reproduction device
510
to record or reproduce information on a desired information track
504
, the information track
504
must be selected accurately. In general, the operation of selecting an information track is call track access, or simply access, and it comprises the operations of moving the whole optical head
514
in a direction perpendicular to the information track
504
, and moving a portion of the optical system in the optical head
514
, for instance, the object lens
545
, in a direction perpendicular to the information tracks
504
by means of an actuator
548
, the latter operation also being called a track jump operation.
Here, a first example relating to a conventional track jump operation, wherein the relative speed of movement between the optical card and optical head is constant, is described with reference to FIG.
10
and FIG.
11
.
FIG. 10
is a diagram illustrating the relationship between the relative speed of movement of the optical card and time, and their relationship to the pulse voltage applied by the optical information recording and reproduction device to the actuator for moving the optical card and time.
FIG. 11
is a flowchart showing the sequence of a track jump operation in an optical information recording and reproduction device.
In order to record or reproduce information to or from the optical card, the optical recording and reproduction device
510
starts an operation whereby the optical card
500
is moved reciprocally by driving the x direction drive motor
516
, such that the optical card
500
and optical head
514
move relative to each other (step
601
in FIG.
11
), and the MPU
512
applies an acceleration pulse (voltage V
1
) to the x direction drive motor
516
to accelerate the relative speed of movement of the optical card
500
to a prescribed speed v
1
(step
602
; section a in FIG.
10
).
If the movement speed detecting circuit
519
detects that the relative speed of movement of the optical card
500
has reached a prescribed speed v
1
, (hereinafter, all detection of the relative speed of movement of the optical card
500
is carried out by the movement speed detecting circuit
519
), then the optical recording and reproduction device
510
applies a constant-speed pulse (voltage V
2
) for maintaining that speed to the x direction drive motor
516
(step
603
; section b), and performs a recording operation for recording information modulated by the modulating and demodu
Kimura Yasuyuki
Kojima Susumu
Noda Kazuo
Hogan & Hartson LLP.
Kabushiki Kaisha Nippon Conlux
Neyzari Ali
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